Incinerator Blues, Part Two: A Beginner’s Guide to Toxic Ash

By Donella Meadows

–September 10, 1987–

The 3200 tons of garbage on the barge that was rejected by 6 countries has finally found its final destination — an incinerator. Increasingly incinerators, sometimes called mass-burn plants, are becoming the solution to our garbage problem. A thousand of them are likely to be constructed in the next 10 years. The salesmen of the mass-burn companies have probably already called upon your public officials.

My garbage goes to a brand-new mass-burn plant built by Signal Environmental Systems in Claremont, New Hampshire. The plant has been constantly embroiled in regulatory hassles. The issue of the moment is whether the ash from the plant is a hazardous waste. If it is, it must be placed in an expensive, lined, monitored, hazardous-waste facility (none of which exist in our state). If it isn’t, it can go into any old landfill.

The difference will mean millions of dollars to my region, billions of dollars to the incinerator industry. It may determine whether that industry survives. As you might imagine, the agencies that will rule on the hazardousness of incinerator waste are under a lot of pressure.

If you want to be sure that pressure is not overwhelmingly one-sided, get in on the fight. You may need, as I did, a crash course on the basic science of incinerator ash. Here, to save you time, is a beginning.

The Environmental Protection Agency decides whether your ash is hazardous by conducting an extraction procedure toxicity test (known to its friends as EP tox). In the EP tox test dilute acetic acid is poured over ash samples, then they are shaken, and filtered. The leachate is tested for various pollutants, one of the most common of which is lead. If the lead concentration is more than 5 milligrams per liter, the ash is officially hazardous (later this year the threshhold will drop to 2 mg/l). Note that this test doesn’t tell you how much lead is in the ash, only how much comes out.

This is the test the Claremont incinerator flunked for the first three months of its operation. The state of Washington tested ash from seven different incinerators across the U.S. and found all fly-ash samples hazardous under the EP tox test, and all bottom-ash samples hazardous in tests for carcinogens (the ash from Claremont is mixed bottom and fly ash).

The EP tox test is supposed to simulate what would happen to the ash as water percolates through it steadily for 25 years in a landfill. Of course the test isn’t the same as what would happen in the landfill, and that is the source of much debate.

To help understand that debate, here are some more useful facts:

1. Heavy metals such are lead are indestructable. They are basic elements, and though they may undergo chemical transformations and may move about in the environment, they never disappear, they are never rendered harmless.

2. Heavy metals accumulate in the human body, where they interfere with many functions. Lead causes neurological impairment, mental retardation, and hearing loss. Children are especially susceptible.

3. Whatever heavy metals are put into an incinerator come out, either in the stack gases or in the ash. The more you clean them out of the gases, the more they show up in the ash. The Claremont incinerator has a lot of lead in its ash because its baghouse is relatively efficient in removing it from the air.

4. Incinerators don’t create lead, but they do make it more dangerous than it was in the garbage. They concentrate it. They also heat it up, much of it vaporizes, and it recondenses in the scrubber and baghouse, adhering to fine particles of fly ash. These particles are easily blown around, inhaled, or washed away with water and into soil.

5. A “lead immobilizing” process used by Signal reduces lead in the EP tox test — not in the ash. The system (which is an industrial secret) probably affects the solubility of the lead by changing it to lead phosphate; therefore the lead is less likely to wash out in the test. Whether it is less likely to wash out in a landfill is unknown. By the time we find out in 25 years, the Claremont plant will have generated and buried 500,000 tons of ash.

6. Heavy metals in the ash comes from the garbage we throw away. Primary sources of lead are batteries, solder, metal alloys, dyed plastics, and colored inks. Lead has been taken out of black newspaper inks, but it is still present in some colored inks. There are documented instances of children getting lead poisoning from chewing on magazine covers. The only way to keep an incinerator from putting out lead is to stop putting lead into it, either by banning the use of lead where substitutes are available (as in inks) or by recycling objects containing it (such as batteries).

The current discussion is about lead. In the future it might be about cadmium or mercury or dioxins or furans or other pollutants that come out of incinerators. The final fact worth remembering is that we are the ultimate source of these things. We might like to think the garbage disappears forever when the truck hauls it away from the curb, but this is, after all, a small planet, and materials don’t leave it. They just cycle around, and sometimes they come back to haunt you.

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About The Donella Meadows Project

The mission of the Donella Meadows Project is to preserve Donella (Dana) H. Meadows’s legacy as an inspiring leader, scholar, writer, and teacher; to manage the intellectual property rights related to Dana’s published work; to provide and maintain a comprehensive and easily accessible archive of her work online, including articles, columns, and letters; to develop new resources and programs that apply her ideas to current issues and make them available to an ever-larger network of students, practitioners, and leaders in social change. Read More

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